A　series　of　P(VDF-TrFE-CTFE)s　were　synthesized　via　a　well-controlled　chemical　route　including　VDF/CTFE　copolymerization　and　dechlorination　of　P(VDF-CTFE)s　to　convert　CTFE　units　into　TrFE　units.　The　microstructure　and　properties　of　the　terpolymers　were　characterized　and　tested　with　differential　scanning　calorimeter　(DSC),　NMR,　dielectric　constant　and　electric　displacement-electric　field　(D-E)　hysteresis　loop.　Thanks　to　the　clean　reaction　system　and　ambient　reaction　condition　of　VDF/CTFE　copolymerization　and　the　hydrogenation　of　P(VDF-CTFE)s,　the　terpolymers　obtained　with　high　purity　and　uniformity　exhibit　a　high　electric　breakdown　field　of　over　500　MV/m,　as　a　result,　the　highest　energy　density　is　obtained　as　10.3　J/cm(3).　Via　comparing　the　structure　and　properties　of　terpolymers;　with　different　compositions　and　from　different　preparing　processes　side-by-side,　the　TrFE　content　and　the　method　of　TrFE　introduced　are　found　to　strongly　affect　the　microstructure　of　the　materials　and　consequently　the　dielectric　properties.　The　advantages　including　the　lower　cost　of　materials,　convenience　of　the　materials　preparation　and　relatively　lower　energy　loss　make　it　possible　to　be　employed　as　capacitor　material.　(C)　2008　Elsevier　Ltd.　All　rights　reserved.